From 591bddea8d874e1500921de0353818e5586618f5 Mon Sep 17 00:00:00 2001 From: Palmer Dabbelt Date: Mon, 24 Jun 2019 01:59:51 -0700 Subject: RISC-V: Add support for the Zicsr extension The various CSR instructions have been split out of the base ISA as part of the ratification process. This patch adds a Zicsr argument, which disables all the CSR instructions. Signed-off-by: Palmer Dabbelt Reviewed-by: Alistair Francis --- target/riscv/cpu.c | 1 + target/riscv/cpu.h | 1 + target/riscv/csr.c | 6 ++++++ 3 files changed, 8 insertions(+) (limited to 'target/riscv') diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c index bbad39a..915b9e7 100644 --- a/target/riscv/cpu.c +++ b/target/riscv/cpu.c @@ -442,6 +442,7 @@ static Property riscv_cpu_properties[] = { DEFINE_PROP_BOOL("u", RISCVCPU, cfg.ext_u, true), DEFINE_PROP_BOOL("Counters", RISCVCPU, cfg.ext_counters, true), DEFINE_PROP_BOOL("Zifencei", RISCVCPU, cfg.ext_ifencei, true), + DEFINE_PROP_BOOL("Zicsr", RISCVCPU, cfg.ext_icsr, true), DEFINE_PROP_STRING("priv_spec", RISCVCPU, cfg.priv_spec), DEFINE_PROP_BOOL("mmu", RISCVCPU, cfg.mmu, true), DEFINE_PROP_BOOL("pmp", RISCVCPU, cfg.pmp, true), diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h index ba551cd..0adb307 100644 --- a/target/riscv/cpu.h +++ b/target/riscv/cpu.h @@ -224,6 +224,7 @@ typedef struct RISCVCPU { bool ext_u; bool ext_counters; bool ext_ifencei; + bool ext_icsr; char *priv_spec; char *user_spec; diff --git a/target/riscv/csr.c b/target/riscv/csr.c index de67741..e0d4586 100644 --- a/target/riscv/csr.c +++ b/target/riscv/csr.c @@ -793,6 +793,7 @@ int riscv_csrrw(CPURISCVState *env, int csrno, target_ulong *ret_value, { int ret; target_ulong old_value; + RISCVCPU *cpu = env_archcpu(env); /* check privileges and return -1 if check fails */ #if !defined(CONFIG_USER_ONLY) @@ -803,6 +804,11 @@ int riscv_csrrw(CPURISCVState *env, int csrno, target_ulong *ret_value, } #endif + /* ensure the CSR extension is enabled. */ + if (!cpu->cfg.ext_icsr) { + return -1; + } + /* check predicate */ if (!csr_ops[csrno].predicate || csr_ops[csrno].predicate(env, csrno) < 0) { return -1; -- cgit v1.1